首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3759篇
  免费   278篇
  国内免费   13篇
耳鼻咽喉   53篇
儿科学   159篇
妇产科学   63篇
基础医学   405篇
口腔科学   87篇
临床医学   525篇
内科学   635篇
皮肤病学   27篇
神经病学   171篇
特种医学   318篇
外国民族医学   1篇
外科学   577篇
综合类   94篇
一般理论   2篇
预防医学   496篇
眼科学   52篇
药学   252篇
  1篇
肿瘤学   132篇
  2021年   34篇
  2020年   27篇
  2019年   49篇
  2018年   61篇
  2017年   40篇
  2016年   52篇
  2015年   59篇
  2014年   80篇
  2013年   112篇
  2012年   147篇
  2011年   150篇
  2010年   133篇
  2009年   110篇
  2008年   145篇
  2007年   133篇
  2006年   140篇
  2005年   141篇
  2004年   154篇
  2003年   122篇
  2002年   120篇
  2001年   101篇
  2000年   97篇
  1999年   88篇
  1998年   107篇
  1997年   106篇
  1996年   106篇
  1995年   77篇
  1994年   65篇
  1993年   65篇
  1992年   85篇
  1991年   75篇
  1990年   64篇
  1989年   70篇
  1988年   78篇
  1987年   75篇
  1986年   65篇
  1985年   64篇
  1984年   53篇
  1983年   46篇
  1982年   37篇
  1981年   32篇
  1980年   32篇
  1979年   42篇
  1977年   27篇
  1976年   30篇
  1975年   31篇
  1974年   36篇
  1973年   29篇
  1972年   30篇
  1966年   24篇
排序方式: 共有4050条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: Propionibacterium acnes is increasingly recognized as a cause of post-neurosurgical infection. This review of patients with P. acnes neurosurgical infection was carried out in order to determine clinical characteristics and outcomes in relation to duration of antimicrobial treatment. METHODS: We retrospectively reviewed the charts of consecutive patients with P. acnes isolated from neurosurgical specimens from 1 January 1999 to 30 June 2005. We defined P. acnes neurosurgical infection as isolation of P. acnes alone from a sterile neurosurgical site in a patient who clinically improved following treatment with an appropriate antibiotic. RESULTS: We identified 28 patients with definite P. acnes neurosurgical infection; median age 49 years (range 23-77); 15 (54%) male. All patients had prior neurosurgical procedures: 27 (96%) post-craniotomy. The median time from surgery to presentation was 54 days (range 12-1,578). Eighteen out of 28 (64%) patients who met the definition of neurosurgical infection had Gram-positive bacilli seen in at least one surgical specimen compared with only 2/56 (4%) patients who did not meet the definition (P < 0.0001). Intravenous benzyl penicillin +/- oral penicillin VK was the most common treatment. The median duration of antibiotic treatment for intracranial infection was 29 days. Five of nine patients who had extracranial bone-flap-associated infection had 相似文献   
62.
Poyser N  Porter R  Briggs P  Kelleher M 《Dental update》2007,34(5):262-4, 266-8
The second part of this paper discusses strategies for providing restorative dental care for the parafunctional patient.These include direct composite resin restorations, cast metal resin-retained restorations and dentine-bonded crowns, design features for porcelain fused to metal crowns and denture design. Specific features can help enhance predictability in the hostile environment of increased occlusal loading and parafunction. CLINICAL RELEVANCE: Appropriate planning, design and execution of restorative procedures can reduce the chance of failure. Patients may have to accept a compromise between appearance and restoration survival/maintenance.  相似文献   
63.
Evidence from animal and human studies suggests that ocular growth is influenced by visual experience. Reduced retinal image quality and imposed optical defocus result in predictable changes in axial eye growth. Higher order aberrations are optical imperfections of the eye that alter retinal image quality despite optimal correction of spherical defocus and astigmatism. Since higher order aberrations reduce retinal image quality and produce variations in optical vergence across the entrance pupil of the eye, they may provide optical signals that contribute to the regulation and modulation of eye growth and refractive error development. The magnitude and type of higher order aberrations vary with age, refractive error, and during near work and accommodation. Furthermore, distinctive changes in higher order aberrations occur with various myopia control treatments, including atropine, near addition spectacle lenses, orthokeratology and soft multifocal and dual-focus contact lenses. Several plausible mechanisms have been proposed by which higher order aberrations may influence axial eye growth, the development of refractive error, and the treatment effect of myopia control interventions. Future studies of higher order aberrations, particularly during childhood, accommodation, and treatment with myopia control interventions are required to further our understanding of their potential role in refractive error development and eye growth.  相似文献   
64.
65.
66.
Adequate pain control is vital in perioperative care. Pain affects respiratory and cardiovascular function with knock-on effects on many other organs and systems. Surgery is also recognized as one of the most frequent causes of chronic pain with surgical approach and level of pain experienced being modifiable risk factors for the development of chronic post-surgical pain.  相似文献   
67.
ObjectivesTo compare different chronic obstructive pulmonary disease (COPD) cost-effectiveness models with respect to structure and input parameters and to cross-validate the models by running the same hypothetical treatment scenarios.MethodsCOPD modeling groups simulated four hypothetical interventions with their model and compared the results with a reference scenario of no intervention. The four interventions modeled assumed 1) 20% reduction in decline in lung function, 2) 25% reduction in exacerbation frequency, 3) 10% reduction in all-cause mortality, and 4) all these effects combined. The interventions were simulated for a 5-year and lifetime horizon with standardization, if possible, for sex, age, COPD severity, smoking status, exacerbation frequencies, mortality due to other causes, utilities, costs, and discount rates. Furthermore, uncertainty around the outcomes of intervention four was compared.ResultsSeven out of nine contacted COPD modeling groups agreed to participate. The 5-year incremental cost-effectiveness ratios (ICERs) for the most comprehensive intervention, intervention four, was €17,000/quality-adjusted life-year (QALY) for two models, €25,000 to €28,000/QALY for three models, and €47,000/QALY for the remaining two models. Differences in the ICERs could mainly be explained by differences in input values for disease progression, exacerbation-related mortality, and all-cause mortality, with high input values resulting in low ICERs and vice versa. Lifetime results were mainly affected by the input values for mortality. The probability of intervention four to be cost-effective at a willingness-to-pay value of €50,000/QALY was 90% to 100% for five models and about 70% and 50% for the other two models, respectively.ConclusionsMortality was the most important factor determining the differences in cost-effectiveness outcomes between models.  相似文献   
68.

Objective

To estimate the cost-effectiveness of adding a selective phosphodiesterase-4 inhibitor, roflumilast, to a long-acting bronchodilator therapy (LABA) for the treatment of patients with severe-to-very severe chronic obstructive pulmonary disease (COPD) associated with chronic bronchitis with a history of frequent exacerbations from the UK payer perspective.

Methods

A Markov model was developed to predict the lifetime cost and outcomes [exacerbations rates, life expectancy, and quality-adjusted life years (QALY)] in patients treated with roflumilast, which showed a reduction in the exacerbation rates and lung function improvement in a pooled analysis from two clinical trials, M2-124 and M2-125. Sensitivity analyses were conducted to explore the impact of uncertainties on the cost-effectiveness.

Results

The addition of roflumilast to concomitant LABA reduced the number of exacerbations from 15.6 to 12.7 [2.9 (95 % CI 0.88–4.92) exacerbations avoided] and increased QALYs from 5.45 to 5.61 [0.16 (95 % CI 0.02–0.31) QALYs gained], at an incremental cost of £3,197 (95 % CI £2,135–£4,253). Cost in LABA alone and LABA + roflumilast were £16,161 and £19,358 respectively. The incremental cost-effectiveness ratios in the base case were £19,505 (95 % CI £364–£38,646) per quality-adjusted life-year gained and 18,219 (95 % CI £12,697–£49,135) per life-year gained. Sensitivity analyses suggest that among the main determinants of cost-effectiveness are the reduction of exacerbations and the case fatality rate due to hospital-treated exacerbations. Probabilistic sensitivity analysis suggests that the probability of roflumilast being cost-effective is 82 % at willingness-to-pay £30,000 per QALY.

Conclusions

The addition of roflumilast to LABA in the treatment of patients with severe-to-very severe COPD reduces the rate of exacerbations and can be cost-effective in the UK setting.  相似文献   
69.
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号